Electric telegraph.



No.,689,4|-5. Patentgdi Dec. 24, IDOL if. A. RQWLAND.

'EILEGIMB TELEGRAPH. (Anvfibaflion filed. Ear. 11, 1901.

(H0 Model.)

T T T T T T T T T T T UNITED STATES PATENT demon,

HENRY A. ROWLAND, OF BALTIMORE, MARYLAND; HENRIETTA H. ROtVLAND, ADMINISTRATRIX OF SAID HENRY A. ROWVLAND, DECEASED, ASSIGNOR TO ROWLAND TELEGRAPHIC COMPANY, OF BALTIMORE, MARYLAND, A CORPORATION OF NEIV JERSEY.

'ELECTRIOTELEGRAPH.

s'rrtc'rntcn rron forming part of Letters Patent No. 689,415, dated December 24, 1901.

Application filed March 11, 1901. Serial No. 50 721. (No model.)

To aZZ whom it may concern: ing the employment of a main-line relay,

Be it known that I, HENRY A. ROWLAND, a either neutral or polarized,which will respond 5o citizen of the United States, residing at Balto the modified and unmodified impulses in timore, in the State of Maryland, have insuch a manner as to energize local selecting- 5 vented certain new and usefullmprovements relays in combinations determined by the in Electric Telegraphs, (Case 11;) and I do combinations of the modified and unmodified herebydeclarethefollowingtobeafull,clear, line impulses, and causing these selecting- 55 and exact description of the invention, such relays to set up a signal-recording impulse as will enable others skilledin the art to which adapted to actuatea type-printing machine. [0 it appertains to make and use the same. Though the employment'ot' the main-line re- This invention relates to improvements in lay is embraced in the main idea prevailing electric telegraphs, and more particularly to inall of the devices referred to, they also 60 an improved method of transmitting intelliembody the idea of passing the line-current gence over an alternating-current circuit by directly through the local selecting-relays by 15 selecting for each signal or character a prethe interposition of a current-selecting dedetermined number of the current impulses vice.

and modifying them by changing their polar- It has formerly been mypractice to modify 65 ity, but otherwise maintaining their form the line impulses by changing their form or and characteristics. to entirely obliterate them, as by cutting This invention contemplates also the divithem out; but in some cases that method has sion of the line-current impulses into groups, not the advantages of the present one, which each of said groups corresponding to a charconsists simply in reversing the polarity of 70 acter or signal and in which apredetermined the impulses without otherwise changing number of the impulses are reversed in sign, their form or characteristics. According to the order and relation of the reversed with the latter method the tongue of arelay acted respect to the normal impulses of a group deupon by a reversed impulse is held against termining the signal or the character of the its contact more firmly than would be the 7 5 code. case if the impulse were simply missing or I In carrying out my said invention 1 introcut out or reduced in intensity. The prinduce into the alternating-current circuit a cipal advantage, however, of the method of mechanism by which at will I may at any reversing the wave over that of cutting it moment reverse the connections of the source out is that by the former (reversed-Wave 80 of alternating currents, so as to' reverse the method) reversing two or more adjacent impolarity of any desired impulse'or any numpulses of a group may form a combination her of impulses. when received upon apolarized relay, where- The said invention contem plates the recepas with the cut-out wave this cannot be done, tion of signals sent in the above manner in forif a polarized tongue is vibrated by an al- 85 any way which will properly interpret them. ternatiug current the effect of cutting out I prefer, however, to interpret the messages two adjacent impulses will be the same as o upon such receivers as those shown and decutting out a single impulse, as the tongue scribedin Patent No. 622,636, granted to me will remain against the contact to which it on April 4, 1899, or upon such as those shown was last sent until an impulse of the opposite c in my pending applications, Serial Nos. sign arrives, while in the case of the reversed 646,017, 659,629, 74:1,956, and 19,070, filed July impulse adjacent impulses may form a com;-

26, 1897, November 23, 1897, December 29, bination, since each will act dilferentlyupon' V 1899, and June 4, 1900, respectively, the the relay, and in this way a greater number main feature of all of these devices, as far as of combinations may be gotten from a given 5 the reception of the signals is concerned, benumber of impulses, which in turn reduces cipleof mysaid invention.

the number of local selecting-relays when this method is employed with the receivers described in theabove-meutioned patent and patent applications.

In order that the nature and objects of my said invention may be more fully understood, the same will be described in greater detail with reference to the accompanying drawings, which represent for illustrative purposes a means for carrying out this invention.

Figure 1 is adiagram illustrating the prin- Fig. 2 represents parts of the transmitter of Fig. 1 as they appear when sending asignal to line. Fig. 3 is a diagram showing a different manner of connecting the transmitter of Figs. 1 and 2. Fig. at is a diagram representing a group of alternating-current impulses modifiedaccording to my invention; and Fig. 5 represents in diagram a series of polarized relay tongues and. stops, showing the relative position of said tongues with respect to the impulses which actuate them.

Similar characters refer' to similar parts throughout the several views.

I shall first describe, briefly, a special form of apparatus for carrying out myinvention and then the manner in which the same isto contact-levers e andf of an ordinary polechanging transmitter g, which is provided also with adjustable forward stops h h and back stops 1' i, pivoted strikerj, which is adapted to vibrate between the contactends of the levers e and f, and with the electromagnet 7a, which actuates the said striker. The contact-stops h and h are permanently connected to the main-line Wire Z, although both are not always in circuit with it, as will hereinafter appear, and the striker is connected to the ground, as shown.

, The stops of the transmitter, especially the forward stops h and h, are capable of accurate adj nstment, so that the sparking and the time of short-circuiting the alternaton,will be reduced to a minimum. Even though the alternator is short-circuited in the operation of the transmitter in effecting the change over or reversal, the time is so extremely short that the self-induction of the alternator will prevent the current from rising to a sufficient extent to be appreciable or to produce any injurious effects. Moreover, the reversal oc curs at or about the point of zero electromot-ive force, which is an additional reason for the fact that no injurious effect is produced by the short circuit. 1

From the transmitting apparatus the linewire Z passes to the desired receiving-station, where it is connected to suitable receiving apparatus, which I have represented in the drawings as a polarized line-relay 8, though various other devices may be employed, as will also hereinafter more fully appear. From the relay 5 the line-wire passes to the ground, as shown.

As a part of the transmitting apparatus I employ the sunflower m, composed of a number of insulated metallic segments-say, for example, fifty-two-and over these segments sweeps a trailer a, mounted upon an arm 19, driven by any suitable power, preferably by the alternator through suitable gearing q q. The width of the segments of this sunflower and the velocity of the trailer are such that the said trailer passes 'over one segment for each impulse or semicycle of the current generatedthat is to say, if there are fifty-two segments in the sunflower the alternator generates once in each revolution of its armature fifty-two semicycles, or twenty-six complete alternations or periods. The segments of the sunflower are divided into a number of separate groups, consisting, say, of eleven segments each, one of such groups being represented as composed of the segments 1 to 11, inclusive. Each of the said segments is connected through a proper circuit making and breaking device, such as a keyboard, perforated or other prepared tape, or the like, with the coil of the electromagnet 70, only two keys 0" and r of a keyboard being shown. The individual keys of each keyboard arein this special case so arranged that each when operated connects in the transmitter-magnet circuit two different segments of the sunflower of the group operated by that particular keyboard or equivalent device. Hence it is possible to connect the segments of the group specified to the transmitter-magnet in fifty-five combinations, taking two segments for each combination, so that if we allow each combination to represent a signal fifty-five signals may be transmitted from a group of eleven impulses. Av battery 0 or other source of local direct current is connected to the trailer and to one terminal of the transmittermagnet'coil, as shown.

The manner of carrying out my said invention is as follows: Let it be assumed that the generatora is delivering an uninterrupted alternating current to the wires 12 and o and that no signals are being sent to line. Then the successive positive and negative impulses will take the following courses through the transmitter to line and back to the alternator, and the reverse: Oneimpulse (positive, for example) will pass from the wire I) through the contact-lever e, forward stop h, the former being normally held against the said stop by the spring 6', and thence to the line Z, which passes to the receiving-station, and in the IIC special case shown in Fig. 1 this impulse will traverse the coil of the relays, returning through earth to the striker j, and then into the lever-arm f, against which arm the said striker is normally held by the spring j. From the lever-arm f the impulse will pass through the wire 0 back to the generator. The next succeeding or negative impulse, as will be readily understood, will traverse the same parts, but in a reverse direction. As long as this operation continues the tongue of the relays will continue to vibrate between its contact-stops in unison with these impulses. Let it be assumed next that for each character or signal to be transmitted there is a corresponding group of impulseseleven, for example-that pass to the line, but that out of this group there is selected for each character or signal a certain number-two, for example-which have their relation to the normalimpulses changed. This change of relation is efiected by reversing the polarity of the selected impulses or changing their phase on the line one hundred and eighty degrees, but without otherwise altering their characteristicsthat is, they retain their same 4, which we will assume is the group or combination of the code which represents the letter A, from which it will be seen that the impulses which normally would have been impulses No. 3 positive and No. 8 negative are now still Nos. 3 and 8, buthave'opposite signs to that which they would have normally, so that wherever there is an impulse modified in this manner there will be a series or set of three of the same sign, and hence where there are two modified in each group this gives rise to two sets of three impulses each in every group. Assuming now any arbitrary character, such as the letter A, the manner in which the impulses are modified to represent this letter is as follows: The operator desiring to send the letter operates, for example, the key 1'. This will connect segments 3 and 8 of the group 1-11 to the transmittermagnet coil.- Then as soon as the trailer starts upon segment 1 the propagation of an impulse corresponding to the first impulse on the left, Fig. 4, will commence, rise to its maximum as the trailer reaches the-center of the segment, and then descend to zero, arriving at that point as the trailer leaves the segment. In order, though, for this to take place, it is first necessary to adjust the sunflower until the spaces or insulation between its segments will exactly corforce, the former being the region of minimum. sparking. As the trailer then reaches segment 2 the second impulse will be sent to line in the same manner, but of opposite polarity to the one preceding it; but when thetrailer begins to pass upon segment 3 this will complete the circuit from the local battery through the coil of the transmitter-magnet, which circuit will remain completed for the length of acomplete impulse, beginning at the point where the last preceding impulse left off or the point of zero-current. At the instant, however, that this circuit is completed the said magnet becomes energized and attracts its armature, which is carried by the striker j. This, as will readily be seen, sends the striker to the right, when its hammer portion will engagethe contact-lever e, and the lever f, hitherto engaged by it, will be sent by its spring against the stop h, as shown inFig. 2. As the last positive impulse passed to line from the wire I) by way of the contact-stop h the present impulse takes the opposite'direction, whence it becomes upon the line a negative impulse passing to line by way of lever e, striker j, and thence to earth, returning by way of line Z and stop h. As soon, however, as the trailer passes off of segment 3 the local circuit will be broken, when the striker will quickly be returned by spring j back to the position shown in Fig. 1. The succeeding fourth, fifth, sixth, and seventh impulses will then pass to line, as described for the first two, but when the trailer reaches segment 8 the local circuit will again be completed through the coil of the transmittermagnet, since segment 8 is connected with said coil through the key 1". When this takes place, the parts of thetransmitter again assume the positions shown in Fig. 2,When the impulse No. 8, normally negative, will pass to line as a positive impulse,'which will begin at thepoint of zero-current, rise to its maximum, and then descend again to zero, when the trailer will pass from segment 8 and the succeedingimpulses pass to'line in the normal positions. Byasimilaroperationany otherarbitrary sign or character may be transmitted, it being necessary simply to select a different combination of impulses in each group for the respective signals, so that in this way we have a clearly-defined telegraphic code, the characters or signs of which may be recorded in various Ways-as, for example, upon a typeprinting machine, chemically or otherwise prepared tape, as upon a Bain receiver or upona Morse register, or in any of'the wellknownways. The relay 8 comprises a part of the printing telegraphic apparatus shown and described in my several patent applications for improvements in electric telegraphs above referred to, the function of the said relay being simply to vibrate its tongue in unison with the alternating current between its contact-stops, and thus to periodically complete certain local circuits to the printing apparatus and to alter these local circuits may not be the same.

by remaining against one or the other of its contacts in certain combinations for each signal.

The efiect produced upon the relay 5 by transmitting a signal to line is graphically represented in Fig. 5, which shows the various positions occupied by the relay-tongue during the passage of the group of impulses shown in Fig. lthrough its coils, from which it will be seen that the modified or changed impulses Nos. 3 and 8 cause the relay-tongue to remain against the contact to which it was last attracted. The positions of the tongue, however, would be the same if instead of changing the selected impulses from their normal sign they were simply cut out of the circuit altogether; but the practical result In practice the tongue of the relays is very sensitively mounted, so that once having been thrown against one of its contacts it is very easily carried back to the other, and in the case of the cut-out semicycle there would be no positive force acting to hold it against the stop to which it was last attracted after the impulse which sent it there had died out. Hence in such a case there is more or less danger of an error, as the correct reception of the signal is dependent upon the accuracy of the relay. On the other hand, it will be readily seen that where the impulses are reversed or simply changed from positive to negative, or vice versa, an extra force, due to the current, holds the tongue against the contact to which it was last sent-via, an impulse of the same polarity as the next preceding onc -which insures greater accuracy in the reception of the signals than would otherwise be the case. It will also be noted that if the striker of the transmitter has been sent forward in a direction to reverse an impulse all of the succeeding impulses will be reversed as long as the striker stays over, sending along the line a series of impulses just the same as the normal impulses, but of opposite polarity, it not being necessary to perform-two operations with the transmitter in order to reverse two adjacent impulses. In other words, one operation of the transmitter will reverse as many consecutive impulses as desired. Therefore if there are a series of polarized relays which respond to a corresponding series of reversed impulses it is necessary to operate the transmitter only once to affect the whole series. This is quite an advantage over the method of cutting out waves which does not admit of the use of combinations of consecutive impulses With a polar line-relay, and hence requires a greater number of selecting receiving-relays.

Any apparatus which will suitably and at the proper times complete the transmitter-v magnet circuit may be substituted for that shownsuch, for example, as a prepared tape adapted totravel in synchronism with the alternator or, indeed, any of the well-known devices or such as I may hereafter devise but in practice when employing the sunflower and keyboard the keys of the latter are so arranged that they may be operated at the proper time only and when so operated are locked until the trailer has passed over the segments to which they are connected before they may be again operated, substantially as described in Patent No. 622,636, granted to me on April 4, 1899, and in my patent ap-' plication filed June 4, 1900, and serially numbered 19,070. Therefore, while I have designated the device 9 the transmitter, this apparatus is only a part of the true transmitting apparatus, which comprises, first, the sunflower upon which the messages are set up, whichmessages are sent as the trailer passes over the segments; second, the keys or their equivalents by which the messages are set up upon the sunflower, but which do not actually operate the transmitter g, and, third, the transmitter g.

The sunflower is the equivalent of perforated or other prepared tape and the keys and r the equivalents of the device (usually punchingdevice) for setting the messages up upon the tape. Therefore by'either the de- .vice shown in Fig. 1 or its equivalent tapetransmitter the messages are automatically sent to line, the device shown being what is termed a key-operatedautomatic transmitter, while the tape devices are usually designated simply automatic transmitters.

Having thus described a form of my invention, I do not wish .to confine it to the various particular cases which it was necessary to assume in order to clearly describe the samesuch, for example, as the modification of two impulses in groups of elevenas I may, if desired, select other numbers of impulses, nor do I wish to limit my invention to the sinewave alternating current. as derived from a commercial alternator, as shown, as I may derive the current from any suitable source so long as it is periodically-varying electric current, and likewisewith other special cases herein described; but

- lVhat I do claim, and desire to secure by Letters Patent of the United'Stat'es, is

1. The improvement in the art of telegraphy, which consists in impressing upon the line an electromotive force of a periodicallyvarying character having alternate impulses of opposite polarity, and changing the polarity of a predetermined number of the current impulses to represent a signal, substantially as described. I

2. The improvement in theart of telegraphy, which consists in impressing upon the line an electromotive force of a periodicallyvarying character having alternate impulses of opposite polarity, and changing the polarity of the same number of the result-ant current impulses for each signal, substantially as described. 7

3. The improvement in the art of telegraphy, which consists in impressing upon the linean electromotive force of periodicallyvarying character having alternate impulses of opposite polarity, changing the polarity of a predetermined number of the resultant current impulses for each signal and maintaining the current upon the line unbroken, substantially as described.

4. The improvement in the art of telegraphy, which consists in impressing upon the line an electromotive force of periodicallyvarying character having alternate impulses of opposite polarity, and modifying a preselected number of the current impulses to represent a signal by commencing at a point of zero current and changing the polarity of said impulses, substantially as described.

5. The improvement in the art of telegraphy, which consists in impressing upon the line an electromotive force of periodicallyvarying character having alternate impulses of opposite polarity, and modifying a preselected number of the current impulses to represent a signal by commencing at the point of zero current and changing the polarity of said impulses without altering the form .or other characteristics thereof, substantially as described.

G. The improvement in the art of telegraphy, which consists in impressing an alternating electromotive force of sine or approximately sine wave form upon a line, and modifying a preselected number of the current impulses for each signal by changing the polarity of the said selected impulses substantially as described.

7. The improvement in the art of telegraphy, which consists in impressing an alternating electromotive force of sine or approximately sine wave form upon a line and modifying a preselected number of the current impulses for each signal by beginning at the point of zero current and changing the polarity of the said selected impulses, substantially as described.

8. The improvement in the art of telegraphy, which consistsin impressing upon a line an alternating electromotive force, changing the polarity of a predetermined number of the resultant current impulses to represent a signal,adjusting the times of the commencement of said changes with respect to the phase of the current and electromotive force, so that the said times shall occur at points of zero current, substantially as described.

9. The improvement in the art of telegraphy, which consists in impressing upon a line an alternating electromotive force, changing the polarity of a predetermined number of resultant current impulses to represent a desired signal,adjusting the times of com mencement of said change with reference to the phase of the impressed electromotive forceand resultant current so that the said times shall occur at points of zero current, the selected impulse rising to its maximum, and then descending to zero at a point where it would naturally have been zero had its polaritynot been changed, substantially as described.

10. The improvement in the art of telegraphy, which consists in impressing upon the line an alternating electromotive force, dividing the resultant current impulses into groups, modifying a predetermined number of the impulses of a group by changing the polarity of said impulses, the number and position of said modified impulses relative to the unmodified impulses of each group representing the respective signals transmitted, substantially as described.

11. The improvement; in the art of telegraphy, which consists in impressing upon the line an alternative electromotive force, dividing the resultant current impulses into groups, modifying a predetermined number of the impulses of a group by changing the polarity of said impulses, the number and position of said modified impulses relative to the unmodified impulses of each group representing the respective signals transmitted, and maintaining the current in each group unbroken, substantially as described.

12. The improvement in the art of telegraphy, which consists in impressing upon the line an electromotive force of a periodicallyvarying character, and having alternateimpulses of opposite polarity, dividing the resultant current impulses into groups, modifying a predetermined number of the impulses of a group by commencing at the point of zero current and changing the polarity of said impulses,the number and position of said modified impulses relative to the unmodified impulses of each group representing the sig nal transmitted, substantially as described.

13. The improvement in the art of telegraphy, which consists in impressing upon a line an electromotive force of aperiodically-varying character and having alternate impulses of opposite polarity, causing groups of resultant current impulses to pass a selected point at regular recurring periods of time, selecting from the total number of said impulses comprising a group, impulses predetermined both as to number and position, and modifying these impulses by changing their polarity, substantially as described.

14. The improvement in the art of telegraphy, which consists in impressing upon a line an alternating electromotive force of sineor approximately sine wave form, causing groups of the resultant current impulses to pass a selected point at regular recurring periods of time, selecting from the total number of impulses comprising a groupimpulses predetermined, both as to number and position, modifying these selected impulses by changing the polarity of said impulses and adjusting the times of said change with respect to the phase of the current and electromotive force, so that the said times shall occur at points of zero current, substantially as described.

15. The method of impressing the characters of a telegraphic code upon a line carrying an alternating electric current,which consists in selecting for each character a group of the impulses of said current, each group comprising the same number of impulses, forming a plurality of separate sets of impulses in each group by the reversal of the polarity of one impulse in each set, each set comprising successive distinct; impulses of the same polarity, the position of one set with respect to the otherin a particular group determining the character of the code represented by that group, substantially as described.

16. The method of transmittingintelligence over a line carrying a periodically-varying electric current and having alternate impulses of opposite polarity, which consists in representing a desired signal by a group of unbroken line current impulses, selecting in this group impulses predetermined both as to number and position, and changing the polarity of said selected impulses, substantially as described.

17. The method of transmitting intelligence, which consists in impressing an alternating electromotive force on a line, dividing the alternating current. into groups of impulses, reversing one or more of the said impulses fora signal, and recording the signal by selecting the special group representing the signal from the remaining impulses, substantially as described.

18. The method of transmitting intelligence, which consists in impressing an alternating electromotive force on a line, dividing the alternating current into groups of impulses, reversing two of the said impulses for a signal, and recording the signal by selecting the special group representing the signal from the remaining impulses, substantially as described.

19. The method of transmitting intelligence, which consists in impressing an alternating electromotive force on a line, dividing the alternating current into groups of impulses, one group for each signal to be transmitted, reversing the same number of impulses in each group, the signal being determined by the orderof said reversed impulses, and recording the signal by selecting the special group representing the signal from the remaining impulses, substantially as described.

In testimony whereof I afiix my signature in presence of two witnesses.

HENRY A. ROWLAND.

Witnesses:

J OHN R HOOPER, A. J. GRAPE. 

